The adjustment of 17-hydroxyprogesterone cut-off values for congenital adrenal hyperplasia neonatal screening by GSP according to gestational age and age at sampling

Abstract

Abstract Background Congenital adrenal hyperplasia (CAH) screening is facing great challenges because of a high false-positive rate and a low positive predictive value (PPV). We established and optimized 17-hydroxyprogesterone (17-OHP) cut-off values for CAH neonatal screening using a genetic screening processor (GSP) according to gestational age (GA), birth weight (BW) and age at sampling. Methods The 17-OHP concentrations in dried blood spots were measured by time-resolved immunofluorescence and were grouped in terms of GA, BW and age at sampling for 48,592 newborns. The 99.5th percentile was used to set an initial cut-off value as a reference. Results Significant differences in 17-OHP concentrations were observed among newborns with different GAs and BWs. A significant difference was observed among different sampling age groups. Finally, we defined new multitier cut-off concentrations based on GA and age at sampling. Application of the new cut-off values resulted in a 30% reduction of the positive rate and a 40% increase of the PPV. Conclusions GA, BW and sampling age time influenced the concentrations of 17-OHP. The efficiency of congenital adrenal hyperplasia screening can be substantially improved by adjusting the multitier cut-off value according to GA and age at sampling.